The rockefeller university

Single-domain antibodies ("nanobodies") derived from the variable region of camelid heavy-chain only antibody variants have proven to be widely useful tools for research, therapeutic, and diagnostic applications. In addition to traditional display techniques, methods to generate nanobodies using direct detection by mass spectrometry and DNA sequencing have been highly effective. However, certain technical challenges have limited widespread application. We have optimized a new pipeline for this approach that greatly improves screening sensitivity, depth of antibody coverage, antigen compatibility, and overall hit rate and affinity. We have applied this improved methodology to generate significantly higher affinity nanobody repertoires against widely used targets in biological research- i.e., GFP, tdTomato, GST, and mouse, rabbit, and goat immunoglobulin G. We have characterized these reagents in affinity isolations and tissue immunofluorescence microscopy, identifying those that are optimal for these particularly demanding applications, and engineering dimeric constructs for ultra-high affinity. This study thus provides new nanobody tools directly applicable to a wide variety of research problems, and improved techniques enabling future nanobody development against diverse targets.

Editor's note: This is the 23rd article in a series on clinical research by nurses. The series is designed to be used as a resource for nurses to understand the concepts and principles essential to research. Each column will present the concepts that underpin evidence-based practice-from research design to data interpretation. To see all the articles in the series, go to https://links.lww.com/AJN/A204.

Background: Monoallelic loss-of-function IKZF1 (IKAROS) variants cause B-cell deficiency or combined immunodeficiency, whereas monoallelic gain-of-function (GOF) IKZF1 variants have recently been reported to cause hypergammaglobulinemia, abnormal plasma cell differentiation, autoimmune and allergic manifestations, and infections. Objective: We studied 7 relatives with autoimmune/inflammatory and lymphoproliferative manifestations to identify the immunologic disturbances and the genetic cause of their disease. Methods: We analyzed biopsy results and performed wholeexome sequencing and immunologic studies. Results: Disease onset occurred at a mean age of 25.2 years (range, 10-64, years). Six patients suffered from autoimmune/inflammatory diseases, 4 had confirmed IG4-related disease (IgG4-RD), and 5 developed B-cell malignancies: lymphoma in 4 and multiple myeloma in the remaining patient. Patients without immunosuppression were not particularly prone to infectious diseases. Three patients suffered from life-threatening coronavirus disease 2019 pneumonia, of whom 1 had autoantibodies neutralizing IFN-a. a . The recently described IKZF1 GOF p.R183H variant was found in the 5 affected relatives tested and in a 6-year-old asymptomatic girl. Immunologic analysis revealed hypergammaglobulinemia and high frequencies of certain lymphocyte subsets (exhausted B cells, effector memory CD4 T cells, effector memory CD4 T cells that have regained surface expression of CD45RA and CD282CD57+ 2 CD57 + CD4+ + and CD8+ + T cells, TH2, H 2, and Tfh2 cells) attesting to immune dysregulation. Partial clinical responses to rituximab and corticosteroids were observed, and treatment with lenalidomide, which promotes IKAROS degradation, was initiated in 3 patients. Conclusions: Heterozygosity for GOF IKZF1 variants underlies autoimmunity/inflammatory diseases, IgG4-RD, and B-cell malignancies, the onset of which may occur in adulthood. Clinical and immunologic data are similar to those for patients with unexplained IgG4-RD. Patients may therefore benefit from treatments inhibiting pathways displaying IKAROS-mediated overactivity. (J Allergy Clin Immunol 2024;154:819-26.)

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells ' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

Eukaryotic chromosome segregation requires kinetochores, multi-megadalton protein machines that assemble on the centromeres of chromosomes and mediate attachments to dynamic spindle microtubules. Kinetochores are built from numerous complexes, and there has been progress in structural studies on recombinant subassemblies. However, there is limited structural information on native kinetochore architecture. To address this, we purified functional, native kinetochores from the thermophilic yeast Kluyveromyces marxianus and examined them by electron microscopy (EM), cryoelectron tomography (cryo-ET), and atomic force microscopy (AFM). The kinetochores are extremely large, flexible assemblies that exhibit features consistent with prior models. We assigned kinetochore polarity by visualizing their interactions with micro- tubules and locating the microtubule binder, Ndc80c. This work shows that isolated kinetochores are more dynamic and complex than what might be anticipated based on the known structures of recombinant subassemblies and provides the foundation to study the global architecture and functions of kinetochores at a structural level.

Despite therapeutic efficacy observed with immune checkpoint blockade in advanced melanoma, many tumors do not respond to treatment, representing a need for new therapies. Here, we have generated chimeric antigen receptor (CAR) T cells targeting TYRP1, a melanoma differentiation antigen expressed on the surface of melanomas, including rare acral and uveal melanomas. TYRP1-targeted CART cells demonstrate antigen-specific activation and cytotoxic activity in vitro and in vivo against human melanomas independent of the MHC alleles and expression. In addition, the toxicity to pigmented normal tissues observed with T lymphocytes expressing TYRP1-targeted TCRs was not observed with TYRP1-targeted CAR T cells. Anti-TYRP1 CAR T cells provide a novel means to target advanced melanomas, serving as a platform for the development of similar novel therapeutic agents and as a tool to interrogate the immunobiology of melanomas.

Judy Lieberman is a professor of pediatrics and adjunct professor of genetics at Harvard Medical School and an endowed chair in cellular and molecular medicine. Her lab studies cytotoxic T lymphocytes (CTL), key cells in the immune defense against viral infection and cancer, as well as molecular pathways activated by the granzymes, and how RNA interference (RNAi) regulates cell differentiation in health and disease states. We spoke to Judy about advice for early career researchers, how she first become interested in cytotoxic T lymphocytes, and key people who have provided mentorship across her career.

Direct methods for determining the fidelity of DNA polymerases are robust, with relatively little sample manipulation before sequencing. In contrast, methods for measuring RNA polymerase and reverse transcriptase fidelities are complicated by additional preparation steps that introduce ambiguity and error. Here, we describe a sequencing method, termed Roll-Seq, for simultaneously determining the individual fidelities of RNA polymerases and reverse transcriptases (RT) using Pacific Biosciences single molecule real-time sequencing. By using reverse transcriptases with high rolling-circle activity, Roll-Seq generates long concatemeric cDNA from a circular RNA template. To discern the origin of a mutation, errors are recorded and determined to occur within a single concatemer (reverse transcriptase error) or all concatemers (RNA polymerase error) over the cDNA strand. We used Roll-Seq to measure the fidelities of T7 RNA polymerases, a Group II intron-encoded RT (Induro), and two LINE RTs (Fasciolopsis buski R2-RT and human LINE-1). Substitution rates for Induro and R2-RT are the same for cDNA and second-strand synthesis while LINE-1 has 2.5-fold lower fidelity when performing second-strand synthesis. Deletion and insertion rates increase for all RTs during second-strand synthesis. In addition, we find that a structured RNA template impacts fidelity for both RNA polymerase and RT. The accuracy and precision of Roll-Seq enable this method to be applied as a complementary analysis to structural and mechanistic characterization of RNA polymerases and reverse transcriptases or as a screening method for RNAP and RT fidelity.

Streptococcus pneumoniae carriage studies are crucial to monitor changes induced by use of pneumococcal conjugate vaccines and inform vaccination policies. In this cross-sectional study, we examined changes within the pneumococcal population following introduction of PCV13 in 2015 in the National Immunization Program (NIP), in Portugal. In 2018-2020 (NIP-PCV13), we obtained 1450 nasopharyngeal samples from children <= 6 years attending day-care. We assessed serotypes, antimicrobial resistance, and genotypes (MLST and GPSC) and compared findings with earlier periods: 2009-2010 (pre-PCV13), 2011-2012 (early-PCV13), and 2015-2016 (late-PCV13). Pneumococcal carriage prevalence remained stable at 60.2 %. Carriage of PCV13 serotypes was 10.7 %, markedly reduced compared to pre-PCV13 period (47.6 %). The most prevalent PCV13 serotypes were 19F, 3, and 19A all showing a significant decreasing trend compared to the pre-PCV13 period (from 7.1 % to 4.7 %, 10.1 % to 1.8 %, and 14.1 % to 1.8 %, respectively), a notable observation given the described limited effectiveness of PCV13 against serotype 3. Non-vaccinated children and children aged 4-6 years were more likely to carry PCV13 serotypes (2.5-fold, 95 %CI [1.1-5.6], and 2.9-fold, 95 %CI [1.3-6.8], respectively). The most prevalent non-PCV13 serotypes were 15B/C, 11A, 23B, 23A, and NT, collectively accounting for 51.9 % of all isolates. In total, 30.5 % of all pneumococci were potentially covered by PCV20. Resistance to penicillin (lowlevel) and macrolides increased significantly, from 9.3 % and 13.4 %, respectively, in the late-PCV13 period, to approximately 20 % each, mostly due to lineages expressing non-PCV13 serotypes, nearing pre-PCV13 levels. An expansion of lineages traditionally associated with PCV13 serotypes, like CC156-GPSC6 (serotype 14) and CC193-GPSC11 (serotype 19F), but now predominantly expressing non-PCV13 serotypes (11A, 15B/C, and 24F for GPSC6; and 15A and 21 for GPSC11) was noted. These findings indicate that the pneumococcal population is adapting to the pressures conferred by PCV13 and antimicrobial use and indicate the need to maintain close surveillance.

Nucleosomes constitute the primary unit of eukaryotic chromatin and have been the focus of numerous informative single-molecule investigations regarding their biophysical properties and interactions with chromatin-binding proteins. Nucleosome reconstitution on DNA for these studies typically involves a salt dialysis procedure that provides precise control over the placement and number of nucleosomes formed along a DNA tether. However, this protocol is time-consuming and requires a substantial amount of DNA and histone octamers as inputs. To offer an alternative strategy, an in situ nucleosome reconstitution method for single-molecule force and fluorescence microscopy that utilizes the histone chaperone Nap1 is described. This method enables users to assemble nucleosomes on any DNA template without the need for strong nucleosome positioning sequences, adjust nucleosome density on demand, and use fewer reagents. In situ nucleosome formation occurs within seconds, offering a simpler experimental workflow and a convenient transition into single-molecule measurements. Examples of two downstream assays for probing nucleosome mechanics and visualizing the behavior of individual proteins on chromatin are further described.